feat(router): add "paramsInheritanceStrategy" router configuration option

Previously, the router would merge path and matrix params, as well as
data/resolve, with special rules (only merging down when the route has
an empty path, or is component-less). This change adds an extra option
"paramsInheritanceStrategy" which, when set to 'always', makes child
routes unconditionally inherit params from parent routes.

Closes #20572.

packages/router/src/pre_activation.ts

@@ -21,7 +21,7 @@ import {reduce} from 'rxjs/operator/reduce';
 import {LoadedRouterConfig, ResolveData, RunGuardsAndResolvers} from './config';
 import {ActivationStart, ChildActivationStart, Event} from './events';
 import {ChildrenOutletContexts, OutletContext} from './router_outlet_context';
-import {ActivatedRouteSnapshot, RouterStateSnapshot, equalParamsAndUrlSegments, inheritedParamsDataResolve} from './router_state';
+import {ActivatedRouteSnapshot, ParamsInheritanceStrategy, RouterStateSnapshot, equalParamsAndUrlSegments, inheritedParamsDataResolve} from './router_state';
 import {andObservables, forEach, shallowEqual, wrapIntoObservable} from './utils/collection';
 import {TreeNode, nodeChildrenAsMap} from './utils/tree';
 
@@ -63,11 +63,11 @@ export class PreActivation {
         (canDeactivate: boolean) => canDeactivate ? this.runCanActivateChecks() : of (false));
   }
 
-  resolveData(): Observable<any> {
+  resolveData(paramsInheritanceStrategy: ParamsInheritanceStrategy): Observable<any> {
     if (!this.isActivating()) return of (null);
     const checks$ = from(this.canActivateChecks);
-    const runningChecks$ =
-        concatMap.call(checks$, (check: CanActivate) => this.runResolve(check.route));
+    const runningChecks$ = concatMap.call(
+        checks$, (check: CanActivate) => this.runResolve(check.route, paramsInheritanceStrategy));
     return reduce.call(runningChecks$, (_: any, __: any) => _);
   }
 
@@ -306,11 +306,14 @@ export class PreActivation {
     return every.call(canDeactivate$, (result: any) => result === true);
   }
 
-  private runResolve(future: ActivatedRouteSnapshot): Observable<any> {
+  private runResolve(
+      future: ActivatedRouteSnapshot,
+      paramsInheritanceStrategy: ParamsInheritanceStrategy): Observable<any> {
     const resolve = future._resolve;
     return map.call(this.resolveNode(resolve, future), (resolvedData: any): any => {
       future._resolvedData = resolvedData;
-      future.data = {...future.data, ...inheritedParamsDataResolve(future).resolve};
+      future.data = {...future.data,
+                     ...inheritedParamsDataResolve(future, paramsInheritanceStrategy).resolve};
       return null;
     });
   }

packages/router/src/recognize.ts

@@ -12,7 +12,7 @@ import {Observer} from 'rxjs/Observer';
 import {of } from 'rxjs/observable/of';
 
 import {Data, ResolveData, Route, Routes} from './config';
-import {ActivatedRouteSnapshot, RouterStateSnapshot, inheritedParamsDataResolve} from './router_state';
+import {ActivatedRouteSnapshot, ParamsInheritanceStrategy, RouterStateSnapshot, inheritedParamsDataResolve} from './router_state';
 import {PRIMARY_OUTLET, defaultUrlMatcher} from './shared';
 import {UrlSegment, UrlSegmentGroup, UrlTree, mapChildrenIntoArray} from './url_tree';
 import {forEach, last} from './utils/collection';
@@ -21,15 +21,17 @@ import {TreeNode} from './utils/tree';
 class NoMatch {}
 
 export function recognize(
-    rootComponentType: Type<any>| null, config: Routes, urlTree: UrlTree,
-    url: string): Observable<RouterStateSnapshot> {
-  return new Recognizer(rootComponentType, config, urlTree, url).recognize();
+    rootComponentType: Type<any>| null, config: Routes, urlTree: UrlTree, url: string,
+    paramsInheritanceStrategy: ParamsInheritanceStrategy =
+        'emptyOnly'): Observable<RouterStateSnapshot> {
+  return new Recognizer(rootComponentType, config, urlTree, url, paramsInheritanceStrategy)
+      .recognize();
 }
 
 class Recognizer {
   constructor(
       private rootComponentType: Type<any>|null, private config: Routes, private urlTree: UrlTree,
-      private url: string) {}
+      private url: string, private paramsInheritanceStrategy: ParamsInheritanceStrategy) {}
 
   recognize(): Observable<RouterStateSnapshot> {
     try {
@@ -55,7 +57,7 @@ class Recognizer {
   inheritParamsAndData(routeNode: TreeNode<ActivatedRouteSnapshot>): void {
     const route = routeNode.value;
 
-    const i = inheritedParamsDataResolve(route);
+    const i = inheritedParamsDataResolve(route, this.paramsInheritanceStrategy);
     route.params = Object.freeze(i.params);
     route.data = Object.freeze(i.data);
 

packages/router/src/router.ts

@@ -27,7 +27,7 @@ import {recognize} from './recognize';
 import {DefaultRouteReuseStrategy, DetachedRouteHandleInternal, RouteReuseStrategy} from './route_reuse_strategy';
 import {RouterConfigLoader} from './router_config_loader';
 import {ChildrenOutletContexts} from './router_outlet_context';
-import {ActivatedRoute, ActivatedRouteSnapshot, RouterState, RouterStateSnapshot, advanceActivatedRoute, createEmptyState} from './router_state';
+import {ActivatedRoute, ActivatedRouteSnapshot, RouterState, RouterStateSnapshot, advanceActivatedRoute, createEmptyState, inheritedParamsDataResolve} from './router_state';
 import {Params, isNavigationCancelingError} from './shared';
 import {DefaultUrlHandlingStrategy, UrlHandlingStrategy} from './url_handling_strategy';
 import {UrlSerializer, UrlTree, containsTree, createEmptyUrlTree} from './url_tree';
@@ -249,6 +249,16 @@ export class Router {
    */
   onSameUrlNavigation: 'reload'|'ignore' = 'ignore';
 
+  /**
+   * Defines how the router merges params, data and resolved data from parent to child
+   * routes. Available options are:
+   *
+   * - `'emptyOnly'`, the default, only inherits parent params for path-less or component-less
+   *   routes.
+   * - `'always'`, enables unconditional inheritance of parent params.
+   */
+  paramsInheritanceStrategy: 'emptyOnly'|'always' = 'emptyOnly';
+
   /**
    * Creates the router service.
    */
@@ -611,7 +621,8 @@ export class Router {
         urlAndSnapshot$ = mergeMap.call(redirectsApplied$, (appliedUrl: UrlTree) => {
           return map.call(
               recognize(
-                  this.rootComponentType, this.config, appliedUrl, this.serializeUrl(appliedUrl)),
+                  this.rootComponentType, this.config, appliedUrl, this.serializeUrl(appliedUrl),
+                  this.paramsInheritanceStrategy),
               (snapshot: any) => {
 
                 (this.events as Subject<Event>)
@@ -667,7 +678,7 @@ export class Router {
             if (p.shouldActivate && preActivation.isActivating()) {
               this.triggerEvent(
                   new ResolveStart(id, this.serializeUrl(url), p.appliedUrl, p.snapshot));
-              return map.call(preActivation.resolveData(), () => {
+              return map.call(preActivation.resolveData(this.paramsInheritanceStrategy), () => {
                 this.triggerEvent(
                     new ResolveEnd(id, this.serializeUrl(url), p.appliedUrl, p.snapshot));
                 return p;

packages/router/src/router_module.ts

@@ -278,6 +278,16 @@ export interface ExtraOptions {
    * current URL. Default is 'ignore'.
    */
   onSameUrlNavigation?: 'reload'|'ignore';
+
+  /**
+   * Defines how the router merges params, data and resolved data from parent to child
+   * routes. Available options are:
+   *
+   * - `'emptyOnly'`, the default, only inherits parent params for path-less or component-less
+   *   routes.
+   * - `'always'`, enables unconditional inheritance of parent params.
+   */
+  paramsInheritanceStrategy?: 'emptyOnly'|'always';
 }
 
 export function setupRouter(
@@ -314,6 +324,10 @@ export function setupRouter(
     router.onSameUrlNavigation = opts.onSameUrlNavigation;
   }
 
+  if (opts.paramsInheritanceStrategy) {
+    router.paramsInheritanceStrategy = opts.paramsInheritanceStrategy;
+  }
+
   return router;
 }
 

packages/router/src/router_state.ts

@@ -18,6 +18,7 @@ import {shallowEqual, shallowEqualArrays} from './utils/collection';
 import {Tree, TreeNode} from './utils/tree';
 
 
+
 /**
  * @whatItDoes Represents the state of the router.
  *
@@ -174,6 +175,9 @@ export class ActivatedRoute {
   }
 }
 
+/** @internal */
+export type ParamsInheritanceStrategy = 'emptyOnly' | 'always';
+
 /** @internal */
 export type Inherited = {
   params: Params,
@@ -181,29 +185,43 @@ export type Inherited = {
   resolve: Data,
 };
 
-/** @internal */
-export function inheritedParamsDataResolve(route: ActivatedRouteSnapshot): Inherited {
-  const pathToRoot = route.pathFromRoot;
+/**
+ * Returns the inherited params, data, and resolve for a given route.
+ * By default, this only inherits values up to the nearest path-less or component-less route.
+ * @internal
+ */
+export function inheritedParamsDataResolve(
+    route: ActivatedRouteSnapshot,
+    paramsInheritanceStrategy: ParamsInheritanceStrategy = 'emptyOnly'): Inherited {
+  const pathFromRoot = route.pathFromRoot;
 
-  let inhertingStartingFrom = pathToRoot.length - 1;
+  let inheritingStartingFrom = 0;
+  if (paramsInheritanceStrategy !== 'always') {
+    inheritingStartingFrom = pathFromRoot.length - 1;
 
-  while (inhertingStartingFrom >= 1) {
-    const current = pathToRoot[inhertingStartingFrom];
-    const parent = pathToRoot[inhertingStartingFrom - 1];
-    // current route is an empty path => inherits its parent's params and data
-    if (current.routeConfig && current.routeConfig.path === '') {
-      inhertingStartingFrom--;
+    while (inheritingStartingFrom >= 1) {
+      const current = pathFromRoot[inheritingStartingFrom];
+      const parent = pathFromRoot[inheritingStartingFrom - 1];
+      // current route is an empty path => inherits its parent's params and data
+      if (current.routeConfig && current.routeConfig.path === '') {
+        inheritingStartingFrom--;
 
-      // parent is componentless => current route should inherit its params and data
-    } else if (!parent.component) {
-      inhertingStartingFrom--;
+        // parent is componentless => current route should inherit its params and data
+      } else if (!parent.component) {
+        inheritingStartingFrom--;
 
-    } else {
-      break;
+      } else {
+        break;
+      }
     }
   }
 
-  return pathToRoot.slice(inhertingStartingFrom).reduce((res, curr) => {
+  return flattenInherited(pathFromRoot.slice(inheritingStartingFrom));
+}
+
+/** @internal */
+function flattenInherited(pathFromRoot: ActivatedRouteSnapshot[]): Inherited {
+  return pathFromRoot.reduce((res, curr) => {
     const params = {...res.params, ...curr.params};
     const data = {...res.data, ...curr.data};
     const resolve = {...res.resolve, ...curr._resolvedData};
@@ -352,7 +370,7 @@ function setRouterState<U, T extends{_routerState: U}>(state: U, node: TreeNode<
 }
 
 function serializeNode(node: TreeNode<ActivatedRouteSnapshot>): string {
-  const c = node.children.length > 0 ? ` { ${node.children.map(serializeNode).join(", ")} } ` : '';
+  const c = node.children.length > 0 ? ` { ${node.children.map(serializeNode).join(', ')} } ` : '';
   return `${node.value}${c}`;
 }
 

packages/router/test/integration.spec.ts

@@ -3794,6 +3794,19 @@ describe('Integration', () => {
   });
 });
 
+describe('Testing router options', () => {
+  describe('paramsInheritanceStrategy', () => {
+    beforeEach(() => {
+      TestBed.configureTestingModule(
+          {imports: [RouterTestingModule.withRoutes([], {paramsInheritanceStrategy: 'always'})]});
+    });
+
+    it('should configure the router', fakeAsync(inject([Router], (router: Router) => {
+         expect(router.paramsInheritanceStrategy).toEqual('always');
+       })));
+  });
+});
+
 function expectEvents(events: Event[], pairs: any[]) {
   expect(events.length).toEqual(pairs.length);
   for (let i = 0; i < events.length; ++i) {

packages/router/test/recognize.spec.ts

@@ -8,7 +8,7 @@
 
 import {Routes} from '../src/config';
 import {recognize} from '../src/recognize';
-import {ActivatedRouteSnapshot, RouterStateSnapshot} from '../src/router_state';
+import {ActivatedRouteSnapshot, ParamsInheritanceStrategy, RouterStateSnapshot, inheritedParamsDataResolve} from '../src/router_state';
 import {PRIMARY_OUTLET, Params} from '../src/shared';
 import {DefaultUrlSerializer, UrlTree} from '../src/url_tree';
 
@@ -201,7 +201,7 @@ describe('recognize', () => {
           });
     });
 
-    it('should merge componentless route\'s data', () => {
+    it('should inherit componentless route\'s data', () => {
       checkRecognize(
           [{
             path: 'a',
@@ -214,6 +214,34 @@ describe('recognize', () => {
           });
     });
 
+    it('should not inherit route\'s data if it has component', () => {
+      checkRecognize(
+          [{
+            path: 'a',
+            component: ComponentA,
+            data: {one: 1},
+            children: [{path: 'b', data: {two: 2}, component: ComponentB}]
+          }],
+          'a/b', (s: RouterStateSnapshot) => {
+            const r: ActivatedRouteSnapshot = s.firstChild(<any>s.firstChild(s.root)) !;
+            expect(r.data).toEqual({two: 2});
+          });
+    });
+
+    it('should inherit route\'s data if paramsInheritanceStrategy is \'always\'', () => {
+      checkRecognize(
+          [{
+            path: 'a',
+            component: ComponentA,
+            data: {one: 1},
+            children: [{path: 'b', data: {two: 2}, component: ComponentB}]
+          }],
+          'a/b', (s: RouterStateSnapshot) => {
+            const r: ActivatedRouteSnapshot = s.firstChild(<any>s.firstChild(s.root)) !;
+            expect(r.data).toEqual({one: 1, two: 2});
+          }, 'always');
+    });
+
     it('should set resolved data', () => {
       checkRecognize(
           [{path: 'a', resolve: {one: 'some-token'}, component: ComponentA}], 'a',
@@ -307,7 +335,7 @@ describe('recognize', () => {
             });
       });
 
-      it('should match (non-termianl) when both primary and secondary and primary has a child',
+      it('should match (non-terminal) when both primary and secondary and primary has a child',
          () => {
            const config = [{
              path: 'parent',
@@ -579,7 +607,7 @@ describe('recognize', () => {
           });
     });
 
-    it('should merge params until encounters a normal route', () => {
+    it('should inherit params until encounters a normal route', () => {
       checkRecognize(
           [{
             path: 'p/:id',
@@ -606,6 +634,25 @@ describe('recognize', () => {
             checkActivatedRoute(c, 'c', {}, ComponentC);
           });
     });
+
+    it('should inherit all params if paramsInheritanceStrategy is \'always\'', () => {
+      checkRecognize(
+          [{
+            path: 'p/:id',
+            children: [{
+              path: 'a/:name',
+              children: [{
+                path: 'b',
+                component: ComponentB,
+                children: [{path: 'c', component: ComponentC}]
+              }]
+            }]
+          }],
+          'p/11/a/victor/b/c', (s: RouterStateSnapshot) => {
+            const c = s.firstChild(s.firstChild(s.firstChild(s.firstChild(s.root) !) !) !) !;
+            checkActivatedRoute(c, 'c', {id: '11', name: 'victor'}, ComponentC);
+          }, 'always');
+    });
   });
 
   describe('empty URL leftovers', () => {
@@ -722,8 +769,11 @@ describe('recognize', () => {
   });
 });
 
-function checkRecognize(config: Routes, url: string, callback: any): void {
-  recognize(RootComponent, config, tree(url), url).subscribe(callback, e => { throw e; });
+function checkRecognize(
+    config: Routes, url: string, callback: any,
+    paramsInheritanceStrategy?: ParamsInheritanceStrategy): void {
+  recognize(RootComponent, config, tree(url), url, paramsInheritanceStrategy)
+      .subscribe(callback, e => { throw e; });
 }
 
 function checkActivatedRoute(

packages/router/test/router.spec.ts

@@ -498,7 +498,7 @@ function checkResolveData(
     future: RouterStateSnapshot, curr: RouterStateSnapshot, injector: any, check: any): void {
   const p = new PreActivation(future, curr, injector);
   p.initialize(new ChildrenOutletContexts());
-  p.resolveData().subscribe(check, (e) => { throw e; });
+  p.resolveData('emptyOnly').subscribe(check, (e) => { throw e; });
 }
 
 function checkGuards(

packages/router/testing/src/router_testing_module.ts

@@ -9,7 +9,7 @@
 import {Location, LocationStrategy} from '@angular/common';
 import {MockLocationStrategy, SpyLocation} from '@angular/common/testing';
 import {Compiler, Injectable, Injector, ModuleWithProviders, NgModule, NgModuleFactory, NgModuleFactoryLoader, Optional} from '@angular/core';
-import {ChildrenOutletContexts, NoPreloading, PreloadingStrategy, ROUTES, Route, Router, RouterModule, Routes, UrlHandlingStrategy, UrlSerializer, provideRoutes, ɵROUTER_PROVIDERS as ROUTER_PROVIDERS, ɵflatten as flatten} from '@angular/router';
+import {ChildrenOutletContexts, ExtraOptions, NoPreloading, PreloadingStrategy, ROUTER_CONFIGURATION, ROUTES, Route, Router, RouterModule, Routes, UrlHandlingStrategy, UrlSerializer, provideRoutes, ɵROUTER_PROVIDERS as ROUTER_PROVIDERS, ɵflatten as flatten} from '@angular/router';
 
 
 
@@ -76,6 +76,13 @@ export class SpyNgModuleFactoryLoader implements NgModuleFactoryLoader {
   }
 }
 
+function isUrlHandlingStrategy(opts: ExtraOptions | UrlHandlingStrategy):
+    opts is UrlHandlingStrategy {
+  // This property check is needed because UrlHandlingStrategy is an interface and doesn't exist at
+  // runtime.
+  return 'shouldProcessUrl' in opts;
+}
+
 /**
  * Router setup factory function used for testing.
  *
@@ -84,9 +91,39 @@ export class SpyNgModuleFactoryLoader implements NgModuleFactoryLoader {
 export function setupTestingRouter(
     urlSerializer: UrlSerializer, contexts: ChildrenOutletContexts, location: Location,
     loader: NgModuleFactoryLoader, compiler: Compiler, injector: Injector, routes: Route[][],
-    urlHandlingStrategy?: UrlHandlingStrategy) {
+    opts?: ExtraOptions, urlHandlingStrategy?: UrlHandlingStrategy): Router;
+
+/**
+ * Router setup factory function used for testing.
+ *
+ * @deprecated As of v5.2. The 2nd-to-last argument should be `ExtraOptions`, not
+ * `UrlHandlingStrategy`
+ */
+export function setupTestingRouter(
+    urlSerializer: UrlSerializer, contexts: ChildrenOutletContexts, location: Location,
+    loader: NgModuleFactoryLoader, compiler: Compiler, injector: Injector, routes: Route[][],
+    urlHandlingStrategy?: UrlHandlingStrategy): Router;
+
+/**
+ * Router setup factory function used for testing.
+ *
+ * @stable
+ */
+export function setupTestingRouter(
+    urlSerializer: UrlSerializer, contexts: ChildrenOutletContexts, location: Location,
+    loader: NgModuleFactoryLoader, compiler: Compiler, injector: Injector, routes: Route[][],
+    opts?: ExtraOptions | UrlHandlingStrategy, urlHandlingStrategy?: UrlHandlingStrategy) {
   const router = new Router(
       null !, urlSerializer, contexts, location, injector, loader, compiler, flatten(routes));
+  // Handle deprecated argument ordering.
+  if (opts) {
+    if (isUrlHandlingStrategy(opts)) {
+      router.urlHandlingStrategy = opts;
+    } else if (opts.paramsInheritanceStrategy) {
+      router.paramsInheritanceStrategy = opts.paramsInheritanceStrategy;
+    }
+  }
+
   if (urlHandlingStrategy) {
     router.urlHandlingStrategy = urlHandlingStrategy;
   }
@@ -128,14 +165,20 @@ export function setupTestingRouter(
       useFactory: setupTestingRouter,
       deps: [
         UrlSerializer, ChildrenOutletContexts, Location, NgModuleFactoryLoader, Compiler, Injector,
-        ROUTES, [UrlHandlingStrategy, new Optional()]
+        ROUTES, ROUTER_CONFIGURATION, [UrlHandlingStrategy, new Optional()]
       ]
     },
     {provide: PreloadingStrategy, useExisting: NoPreloading}, provideRoutes([])
   ]
 })
 export class RouterTestingModule {
-  static withRoutes(routes: Routes): ModuleWithProviders {
-    return {ngModule: RouterTestingModule, providers: [provideRoutes(routes)]};
+  static withRoutes(routes: Routes, config?: ExtraOptions): ModuleWithProviders {
+    return {
+      ngModule: RouterTestingModule,
+      providers: [
+        provideRoutes(routes),
+        {provide: ROUTER_CONFIGURATION, useValue: config ? config : {}},
+      ]
+    };
   }
 }

tools/public_api_guard/router/router.d.ts

@@ -127,6 +127,7 @@ export interface ExtraOptions {
     errorHandler?: ErrorHandler;
     initialNavigation?: InitialNavigation;
     onSameUrlNavigation?: 'reload' | 'ignore';
+    paramsInheritanceStrategy?: 'emptyOnly' | 'always';
     preloadingStrategy?: any;
     useHash?: boolean;
 }
@@ -329,6 +330,7 @@ export declare class Router {
     readonly events: Observable<Event>;
     navigated: boolean;
     onSameUrlNavigation: 'reload' | 'ignore';
+    paramsInheritanceStrategy: 'emptyOnly' | 'always';
     routeReuseStrategy: RouteReuseStrategy;
     readonly routerState: RouterState;
     readonly url: string;